Looks like this thread is due for a bump, which I may as well provide with my little story of dead 12V batteries.

A week into owning our 2013 SL, my wife arrived at the car after work to find it completely dead. No locks, no lights, no anything. A jump started everything up just fine. The traction battery was somewhere around 20% charged at the time.

The next week I brought it into the dealer and had them test the battery. It came back a little weak, so I had them replace it with a new one.

One week later, I came out to the new battery dead just like the first time. The traction battery was similarly at around 20%.

Neither time was the car charging, in accessory mode, lights left on, OBDII port being used, nor key in the car. The dealer has it right now, and is going to keep it overnight to test it when it's asleep. They did mention that there were no error codes when they checked.

The suggestion from the tech was that perhaps the short daily drives of a couple of miles or so were not enough to charge back up the 12V during operation. This seems a little wrong, and wanted to know what anybody thinks of this explanation. We've been charging once a week at L2, driving in either 2-3 mile or 10-20 mile spurts, with the 12V turning up dead two times out of two just before recharging.

This is a stupid problem to have. Can anyone help? I'd like to at least have other suggestions/questions for the dealership when I talk to them again tomorrow.

Thanks!

The 12v battery has a constant drain on it. Not a large one, but a constant one, as do all modern cars loaded with computers. The 12v battery is charged whenever the traction battery is charged. It is also topped off when the car is in run mode. The Leaf charging algorithm is not the best, and driving many short trips and only charging once a week work against you. The tech may not understand why, but he is not wrong.

Since you have a 2013, set the charge timer for 80% and charge at least every other day. Charge it to 100%, at least once a month (I would suggest every two weeks), to keep the cells balanced on the traction battery. Lithium batteries don't do well with constant low or high charge levels. It is better for the battery to have a 10 minute charge cycle every night that brings it up to 80%, than it is to let the level get low and only charge once a week.

It is also possible you have something failing, that is drawing a higher load than it should. One user reported an ABS unit that started having a constant draw on the 12v system that never stopped, even when the car was off. If you have not upgraded your telematics unit, it could also be causing an excess drain trying to connect to a network that is no longer active.

Good to know, thanks. I had the same thought about the telematics unit and mentioned it to the tech today. If they're unable to find a draw on the system, he did mention something about changing the way it charges the 12V battery. I'll update when I have more info.

My situation is this: since I upgraded the telematics unit in December I've gone through four batteries. The first died one week after the upgrade, which I (naively) attributed to the car being 3 years old. The second died two weeks later. The third lasted a month. And the forth lasted a bit over a month. All of the batteries were damaged - discharged to non-recoverable levels (the most recent one read 2.2V which I didn't even know was possible with a 12V battery).

As the only change was the telematics unit upgrade, Occam's Razor suggests it's the culprit. I've taken it to the dealership who neither found the problem nor researched the problem - but charged me $150 for diagnostics and showed me the sterling printout of the battery health report. As the battery was one day old at that point (it was battery #3) it was no surprise that it was indeed in very good shape.

I'm dropping the car off this weekend at the dealership, and will simply not pick it up until I hear from them that they found the problem and resolved it.

Has anyone else had an issue with the 12V battery being abnormally discharged? The only good news is that there'll be the EVSE malfunction (amber exclamation-mark-on-car symbol) that will go on a few days before the 12V is too discharged to start. I've read about this on the forum, and it seems that doing a reset of the telematics unit, fuse-pull, etc. will resolve it, but it hasn't in my case.

It's been incredibly frustrating, and there's no small amount of irony in jump-starting an EV. That too only works before the battery is broken, at the stage when it's merely dead (insert Princess Bride reference about mostly-dead versus completely-dead).

If you think it's the telematic unit, pull the telematic fuse. Search the forums for the fuse location.

Also, since I started this thread 4 years ago, I still may get this problem once a year with a few iterations, however it's always at home and I can jump the car with a portable jumper set that I kept in the glovebox. I'll also keep a battery tender on the 12v battery overnight during these outbursts, every few months to top off, or when I'm out of town a few days. So far so good.

I posted on one of the telematics upgrade threads about the 12-volt battery in my 2015 being drained while parked after having the EV warning light come on two days in a row with DTC code referring to incomplete shutdown. Those error codes happened about 30 days after the upgrade and I did not get charge status updates via email and text on those two days. I parked the car for a few days (EVSE not connected, Bluetooth device unplugged from OBDII port, and everything else properly shut down). The car was completely dead when I returned home so I had to use my booster battery to get it started. The complete discharge of the 12-volt battery must have reset the telematics unit because charge status emails and text messages have been delivered every day since then and there have been no more EV system errors. I thought the deep discharge of the original 12-volt battery would finish it off, but it has worked fine for three months.

Yes, I remember reading your post. Unfortunately, if merely having the battery die completely (of the batteries I've replaced since December the voltages have read as low as 2V, 6V, and 7V - so if that's all it takes to reset the telematics unit - it's been reset several times.

The charge status emails would generally work for about 2 days after a new battery (or I manually charged the 12V) then the battery would be too low for them to function. The confound in this situation was that since the telematics were intermittently working prior to the upgrade and intermittently working after - I suspected the telematics unit and not the 12V battery (only an issue AFTER the upgrade).

The Nissan dealership where I purchased it has the car right now, and I told them that I'm not picking it up until it's resolved. I went back to them as they installed the telematics unit, and so have all the records and so the resolution is incumbent upon them. After this situation is resolved I'll never be back to that dealership again (they have quite a history of exceptionally poor service with me).

Best,Tal

GerryAZ wrote:I posted on one of the telematics upgrade threads about the 12-volt battery in my 2015 being drained while parked after having the EV warning light come on two days in a row with DTC code referring to incomplete shutdown. Those error codes happened about 30 days after the upgrade and I did not get charge status updates via email and text on those two days. I parked the car for a few days (EVSE not connected, Bluetooth device unplugged from OBDII port, and everything else properly shut down). The car was completely dead when I returned home so I had to use my booster battery to get it started. The complete discharge of the 12-volt battery must have reset the telematics unit because charge status emails and text messages have been delivered every day since then and there have been no more EV system errors. I thought the deep discharge of the original 12-volt battery would finish it off, but it has worked fine for three months.

taloyd wrote:The charge status emails would generally work for about 2 days after a new battery (or I manually charged the 12V) then the battery would be too low for them to function. The confound in this situation was that since the telematics were intermittently working prior to the upgrade and intermittently working after - I suspected the telematics unit and not the 12V battery (only an issue AFTER the upgrade).

I've joined the club of dead 12v batteries. All symptoms are similar to what taloyd experienced: After a few days on not receiving charge status notifications (like because the car couldn't connect with the server) and the EV System alarm light is on when I turn on the car, then after the 3rd or 4th day of this the 12v battery is dead. Happens whether I charge the car at home overnight or not. I would then have to use a trickle charger at home to bring it back to life then drive it around to charge it. Dealer visit was not helpful (they ran diagnostics and found nothing wrong with battery or software).

Now that I've turned off all notifications and also unchecked any boxes in Carwings related to downloading data, the 12v battery has not died for the past 3 days and I'm not getting the the EV system alarm light on when I turn on the car. This is my band aid for now.

Dealer still can't understand how the Carwings/notifications is causing the 12v battery to die. They suggested next time the 12v battery dies, I have it towed in to them and they'll run the battery tests overnight to find the problem. But that means no car for 2 days- I can't be carless that long.

taloyd do you have an update on whether Nissan found/fixed your problem?

taloyd do you have an update on whether Nissan found/fixed your problem?

Yes, dealer gave it back after two weeks with the delightful response that they couldn't figure out what's wrong but that "it turned on for three days in a row" (that's verbatim, BTW). They also suggested I take it to another dealer "to get a 2nd opinion". This is the 3rd time it's been to this dealer (where I bought it) for the same issue. Both their two Nissan Leaf techs couldn't figure it out, though the last time it was there the tech found a "stuck inverter relay" which would certainly drain the battery - although the car died the day after I picked it up from them that time, so that was clearly not the only problem.

So still have the car, still have no idea if it'll keep turning on - it's only been 2 days since I got it back. Still thinking about the Hyundai Ioniq.

2015 SV - Telematics upgraded and nothing but warning lights and dead 12v batteries since. Dealer useless..."no problems found". Judging by the number of posts around this issue, I think Nissan has a problem with the telematics unit(s), charging software or something else ....Now the dealer wants to charge me for a loaner car while they look for the issue. Looking at the Volt. Maybe the grass is not greener, but anything is better than having the service guys tell you that there is nothing wrong with your vehicle...over and over again while you keep charging cables in your EV to jump your 12v battery!

Add me to the list. 2015 Nissan Leaf SV with regular 120V charger that came with the car. "12v battery dead" problem started happening a couple of months ago. We would come home and plug it in to charge, and once in a while, we would find it dead in the morning, having to "jump start" it. This was less frequent in the beginning -- weeks between jump starts, and more frequent more recently -- a few days between jump starts.

During this time we took it to the dealer like 4 times, with no luck. Once they replaced the battery, but they said they can't find the problem. This last time they had the car for 8 days and supposedly tried everything, but it did not happen to them. It happens at home, does not happen at the dealer. Wife is frustrated, I'm frustrated, dealer is supposedly frustrated -- they need to replicate it in order to troubleshoot it. Town Center Nissan north of Atlanta, if anyone cares.

I've started to top off the 12v battery with the jump starter as a poor man's charger. I don't know what else to do, but wait it out until STUPID NISSAN AND DEALERS acknowledge this problem and find a solution. This is terrible. I can't with a clear conscience sell the car either. I'm stuck.